Okay, detailed reply for Nepster.
108 replays: With hope, I have fixed the low-hanging fruit already, see post above. I have to dig into the terrain handling code next.
I'm not aiming for 100 % compatibility, but I want to give a solid reason for each incompatibility.
Solid off by 1: Test case (replay with included level) would be nice. I want to get this right at all costs. Let's make it work like in C++ Lix, or come up with a good reason for such a change.
Joystick bug: Collected info on github. I would like to repro this on Icho's Windows machine eventually. This is also rather important. It's very hard to debug: Even a debugging build didn't give a useful stack trace for Clam.
Miner & steel: I haven't been able to reproduce this.
Test case please -- can you provide a replay?
Stay pixels: Part of (I have to dig into the terrain-handling next).
Key stuck: Got an idea already, will try it for the next release today/tomorrow.
FF & lag: I have only bad/complicated ideas so far.
Unimplemted: Screen starting position, automatic only, or manual still? As of 2016-02-10, I lean towards allowing both. So, let's treat it as yet-unimplemented.
Time limit isn't implemented at all yet. It would be handy to count updates since level start, for debugging replays.
Singleplayer should start at update 30, not 0, or maybe even later. Action should happen ASAP, while still looking somewhat good. People are impatient and FF through 2 seconds!
-- Simon